To eliminate, or at least minimize, color differences between devices, you can use ICC (International Color Consortium) color profiles whenever color conversions are made during preflight and correction.
An ICC color profile is a mathematical description of the color space used by a specific device. All objects in your PDF documents, i.e. text, graphics and images, can be associated, or "tagged", with an ICC profile for a given color space (Grayscale, RGB or CMYK).
You can select an ICC profile for each color space in the PitStop Pro preferences. If you want to make separate settings for Images and other objects, select the "Use other settings for images than for objects". The pane underneath will then show two tabs, one for images and one for other objects.
However, you may also be using Preflight Profiles or Action Lists in which ICC profiles have been specified too. In that case, the ICC profiles in the respective Preflight Profiles or Action Lists will take precedence over those which you selected in the PitStop Pro preferences.